The invention concerns a guard placed over a vent, particularly a vent from a dryer apparatus, such as a clothes dryer, and the guard being particularly intended for guarding against birds passing the guard and entering the vent.
Vents, particularly dryer vents, which open outwardly of a building wall to the environment provide an outlet opening which may be entered by birds and possibly by other animals. To avoid that, various types of guards may be arrayed over the vent preventing access into the vent by birds. Various types of vents, particularly a dryer vent, emit not only air or gas, but also lint or dust which may be generated by the apparatus. Surfaces of the guard will be struck by the emitted lint or dirt. Eventually, that will build up on the elements of the guard over which the vented air or gas passes.
Examples of a bird guard over a vent are illustrated in U.S. Pat. Nos. 5,722,181; 5,916,023, Des. 390,948 and Des. 397,431. These guards use intersecting bars which create box shaped openings in the sides of the guard. Such openings keep rodents as well as birds from passing the guard. But, these guards have many surfaces of support bars in the vent outflow, which the present invention is intended to minimize.
It is desirable to minimize the extent to which dirt and lint will build up on the guard. Obviously, the fewer elements and the less material of the guard which is in the direct flow out of the vent, the less likely is a build up of lint or dirt or other materials on the guard. A guard consisting of a relatively small cross section, or small diameter bars or widely spaced bars is preferable, because it presents less surface area to the air or gas being vented and is less likely to develop a blocking layer of material emitted from the vent on a use guard. On the other hand, bars too widely separated may not be close enough to neighboring bars to block passage of a bird past the guard and into the vent.